Garbage grinder



Jan. 12, 1954 R. W. STREH LOW GARBAGE GRINDER Filed May 29, 1950 ROBERTw. STREHLOW INVENTOR. B Z- ATTORNEY Patented Jan. 12, 1954 UNITED STATESATENT 2.5+ FFICE GARBAGE GRINDER Application May 29, 1950, Serial No.164,923

1 Claim. 1

This invention relates to garbage grinders in general and its severalfeatures provide an improved apparatus particularly adapted to thegrinding of waste matters found in the kitchens of hotels, restaurantsand institutions.

It is the general object of this invention to improve the operatingcharacteristics of grinders and to simplify the mechanical maintenancethereof and to eliminate the necessity for frequently cleaning certainportions of the grinder.

It is a further object of this invention to provide in a grinder of thetype utilizing rotating teeth a construction that will facilitatefeeding the garbage to the teeth automatically without the necessity ofcontinually prodding or poking the garbage into the grinder.

Another object of this invention is to provide an improved end discconstruction for garbage grinders of the type having rotatable cuttingdiscs carried by an overhanging motor shaft.

A still further object of this invention is to provide a replaceablecutting tooth insert for grinders oi the aforesaid type and to therebyfacilitate the maintenance of sharp cutting teeth.

According to this invention a series of disclike cutting members areassembled on the shaft of a motor, each disc being in afixedrelationship with respect to the other discs and the disc assemblybeing rotatable as a unit with the a motor shaft. Each cutter disc has araised portion forming a backing and support for a removable rectangularblade portion, such blade portion having a plurality of sharpened edges,any of which may be utilized when mounted in operative cutting position.

The entire cutter disc assembly is contained within a housing in such amanner as to direct garbage to the cutting teeth and limit the passageof garbage between the ends of the cutter disc assembly and the walls ofthe housing. A packing is provided at the point where the motor shaftenters the housing and an annular washer member is provided at theopposite, outer end of the motor shaft, which washer provides anoccasional bearing between the end of the motor shaft and the aforesaidhousing. This washer has a smaller diameter than the cutting discs sothat the exposed portion of the cutter disc assembly is operative in itsentirety to grind garbage. This construction provides a furtheradvantage in that small particles attempting to escape between theoutward end of the cutter disc assembly and its housing arecentrifugally thrown back into the central portion of the 2 housing, aswill be explained subsequently in greater detail.

The cutter disc housing conforms substantially to the circumference ofthe cutter disc through out substantially three quadrants of itscircumference. Into two of these quadrants is inserted a perforatedgrate extending axially of the cutter disc assembly and forming an exitthrough which comminuted particles may pass. This grate in prior artstructures occupied the bottom half of the cutter disc circumference butin this invention it has been displaced approximately 30 in thedirection of rotation of the cutter disc assembly so that a pocketportion might be provided in the housing adjacent the leading edge ofthe grate. This pocket construction traps garbage fed to it from theupper portion of the grinder housing (which forms a feed chute) andbecause of the pocket, garbage is retained or trapped in a position inwhich the cutter teeth may obtain purchase upon it and thereby rapidlycomminute said garbage without the necessity of external poking orprodding.

The invention is more fully described in connection with the drawings inwhich- Fig. l is an end view of the grinder and its housing shown partlyin section;

Fig. 2 is a side view of the grinder, housing and motor, also shownpartly in section; and

Fig. 3 is a detail view of a cutter disc of the type illustrated in Fig.1 and showing a replaceable tooth insert.

Referring to the drawings and in particular to Figs. 1 and 2, garbage isfed into the machine by means of a feed chute ll shown as the upperportion of the grinder housing which is indicated generally as i 2 andwhich provides a chamber in which the rotatable material-disintegratingelement of the apparatus is disposed.

Various types of feed pans may be mounted above the feed chute H. Onesuitable type is that disclosed in the co-pending application of myco-worker, Gilbert W. Quast, Serial No. 247,587, filed September 21,1952, which enables continuous feed and operation of the grinder.However, the grinder may be operated on a batch principle, in whichevent it is only necessary to provide a removable cover over the chute Hto prevent garbage being ground from being thrown out of the feed inlet.

The feed chute i I is tapered so that it diverges downwardly and it istherefore apparent that any pieces of garbage which are capable of entering the chute will pass therethrough and be presented to the cuttingteeth. An orifice it is provided in one side of the feed chute H andcommunicates with an external cup l4 into which water may be suppliedfrom a source [5 to facilitate grinding and flushing.

The cutting portion of the grinder is illustrated as comprising a seriesof co-axial, disc-like members I6 assembled on the overhanginghorizontal shaft H of a motor 58. Each of the discs 16 has a raisedportion it which forms a backing for a replaceable cutter tooth 2B. Thediscs are se-. cured together into a unitary cylindrical rotor elementby means of bolts 2| passed through the discs and threaded into the disci6 adjacent to the motor 18. The cutting surfaces of the respectivediscs are staggered radially of the rotor or cutting assembly so thatadjacent cutting surfaces are not axially aligned. A seal 22 is providedat the entrance point of the motor shaft into the housing i2 whichprevents the passage of water and particles of garbage into the motorhousing.

At the outer end of the motor shaft a washer member 23, concentric withthe cutter discs, is carried by the motor shaft and held firmly againstthe outermost cutting disc it" by means of a nut 24 which, throughfrictional engagement, holds the cutter disc assembly securely on themotor shaft and assures its rotation therewith. This washer 23 is of asmaller diameter than are the cutting discs 16 and fits into a re endsurface of the last cutter disc and the grinder 7 housing are thrownoutwardly because of the rapid speed of rotation of the cutter disc andare thereby prevented from entering the recess 2% in the grinder housingend plate. in normal operation the washer 23 does not contact the endplate surfaces defining the recess 25 but if the motor shaft 1? isdeflected due to hard grinding, the peripheral surface of the washerforms an occasional bearing with a cylindrical portion 28 of the endplate 2'1 and thereby provides a support for the overhanging motor shaftI1 limiting deflection thereof to the clearance between the washerperiphery and the cylindrical portion 23 of the end plate, thuspreventing permanent distortion of the shaft.

A better understanding of the advantages of the end washer constructionhere illustrated is possible in view of the prior art. l-leretofcre ithas been the practice to utilize an end disc or washer of substantiallythe same diameter as the cutting discs and it rotated in a recesssimilar to the recess 26 here illustrated except that the cylindricalportion 28 was of a diameter slightly larger than the cutting discs.With this construction it was necessary to completely fill the recess 28with grease in order to discourage the entry of comminuted particles.However, in operation, the grease was centrifuged into the grindingportion of the housing and escaped into the sewer, after whichcomminuted particles worked into the recess 25 and filled it, creatingan objectionable odor and necessitating frequent cleaning.

The improved construction here illustrated overcomes the greater portionof this difiiculty. The space or running clearance 25 between the lastcutter disc I5 and the housing end plate 2'! lies wholly in a planenormal to the axis of the shaft ii and communicates radially around itsouter periphery with the interior of the grinding chamber. Because ofthe rapid rotation of 4 the cutter disc l5" particles which enter thespace 25 are thrown back into the grinding portion of the housing bycentrifugal force. With the prior art construction, the space 25 was aninverted L shape and did not communicate radially with the grindingchamber with the result that particles could not be thrown clear becausethey struck the horizontal portion of the space and could not escape.The present construction operates for long periods of time withoutbecoming contaminated and grease is not required in the recess 26.

In operation the motor rotates counterclockwise in the direction of thearrow in Fig. 1 and the separate teeth 20 of the cutter discs itcomminute garbage passed through the feed chute H. The comminutedparticles then pass out through a grate or cage 29 occupyingsubstantially 186 of the rotation of the cutter discs and conformingsubstantially with the circumference of their circle of rotation. Thegrate 29 occupies the lower portion of the circle of rotation of thecutter teeth except that it is displaced forward in the direction ofrotation approximately 30. This displacement makes possible the creationof a semi-crescent shaped pocket 35 adjacent the cutting discs it whichis formed by a curved, downwardl converging side 3! of the feed chute H.This pocket tapers into an apex below the axis of the motor shaft andhas an axial length substantially equal to the axial length of thecutter disc assembly.

It has been the usual practice in prior art grinders of this type tolocate the grate 29 on the lower one-half of the circle of rotation ofthe cutter discs and to feed garbage to the upper one-half. Ehispractice had the disadvantage of relying entirely upon the weight of thegarbags for the force necessary to hold it against the cutting teeth andmade it necessary to poke or shove garbage from the top of the chutewith a stick or other apparatus in order to hold it against the teethwith suflicient force to enable them to obtain a purchase and commencetheir grinding action.

The construction here illustrated and described eliminates the greaterportion of this poking because garbage is confined within the pocket 38and held by the downwardly converging pocket side 3'5. As the cutterdiscs rotate, garbage is forced into the more restricted lower portionof the pocket and because of the compacting which results, garbage isforced against the teeth, enabling them to comminute the matter withgreater dispatch.

Flushing water entering through the orifice l3 falls upon the cutterdiscs it and passes with the comminuted garbage through the grate 29thereby facilitating the flushing of ccmminuted particles into the lowerportion 32 of the grinder housing from which the comminuted particlesmay be carried away to a sewer, not shown.

Fig. 3 illustrates a replaceable cutter tooth 2B which fits into a slot33 on the periphery of the cutter disc I6 and is retained by means of astud 34 passing through the tooth and threaded into the cutter disc. Asmay be seen, the cutter disc is formed with a raised portion is whichprovides a backing to retain the cutter tooth. The tooth 2B is furtherretained by contact with the fiat, side faces of adjacent cutter discswhen the separate cutter discs are assembled together as a unit, aspreviously described. The cutter tooth 20 may be formed of a hardmaterial and is preferably made rectangular so that each of its eightlateral edges may be exposed successively as a cutting edge. In thismanner the maintenance of a sharp cutting edge is greatly facilitatedand a tooth need not be sharpened until all eight of its edges havebecome dulled. Further, in order to sharpen the grinding element it isnot necessary to dismantle the cutter discs from the motor shaft as hasbeen necessary in the past due to the fact that the raised portion IQ ofthe cutter disc was itself a cutting edge.

What I claim is:

Apparatus for grinding garbage and the like, comprising a housing havingtwo vertical opposed end walls; a grate extending between said walls toform a grinding chamber; a horizontal rotatable shaft extending throughone of said walls and beyond the plane of the second of such walls; acylindrical rotor element rigidly carried by said shaft within thegrinding chamber and provided with peripheral teeth co-operable withsaid grate to disintegrate the garbage material, said rotor havingvertical end faces having running clearance with the inward faces ofsaid housing walls which clearances have radial straight-linecommunication with the grinding chamber at the periphery of the rotorwhereby disintegrated particles of material finding their way into suchclearance may be readily expelled therefrom into the chamber bycentrifugal force imparted to such particles by the rotor, said secondhousing end wall having a recess therein concentric with and freelyreceiving the portion of the shaft extending beyond the plane of suchwall, said recess having a diameter materially smaller than that of therotor element; a washer mounted on the shaft abutting the rotor anddisposed within said recess with running clearance between the outerperiphery of the washer and the periphery of the recess, said recessproviding substantial clearance around the shaft beyond the washer; andmeans fixedly securing the washer to the shaft for rotation therewith.

ROBERT W. STREHLOW.

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